FEM ConstraintDisplacement: Difference between revisions

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# In the [[3D_view|3D view]] select the object the constraint should be applied to, which can be a vertex (corner), edge, or face.
# In the [[3D_view|3D view]] select the object the constraint should be applied to, which can be a vertex (corner), edge, or face.
# Choose a degree of freedom or prescribe a displacement.
# Choose a degree of freedom or prescribe a displacement.

==Formulas==

{{Version|1.0}}

For the [[Image:FEM_SolverElmer.svg|32px]] [[FEM_SolverElmer|solver Elmer]] it is possible to define the displacement as formula. In this case the solver sets the displacement according to the give formula variable.

Take for example the case that we want to perform a transient analysis. For every time step the displacement <math>d</math> should be increased by 6 mm:

<math>\quad
d(t)=0.006\cdot t
</math>

enter this to the ''Formula'' field:</br>
{{incode| Variable "time"; Real MATC "0.006*tx"}}

This code has the following syntax:
* the prefix ''Variable'' specifies that the displacement is not a constant but a variable
* the variable is the current time
* the displacement values are returned as ''Real'' (floating point value)
* ''MATC'' is the prefix for the Elmer solver that the following code is a formula
* ''tx'' is always the name of the variable in ''MATC'' formulas, no matter that ''tx'' is in our case actually ''t''


==Notes== <!--T:5-->
==Notes== <!--T:5-->

Revision as of 22:21, 24 March 2023

FEM ConstraintDisplacement

Menu location
Model → Mechanical Constraints → Constraint displacement
Workbenches
FEM
Default shortcut
None
Introduced in version
-
See also
FEM tutorial

Description

Creates a FEM constraint for a prescribed displacement of a selected object for a specified degree of freedom.

Usage

  1. There are several ways to invoke the command:
    • Press the FEM ConstraintDisplacement button.
    • Select the Model → Mechanical Constraints → Constraint displacement option from the menu.
  2. In the 3D view select the object the constraint should be applied to, which can be a vertex (corner), edge, or face.
  3. Choose a degree of freedom or prescribe a displacement.

Formulas

introduced in version 1.0

For the solver Elmer it is possible to define the displacement as formula. In this case the solver sets the displacement according to the give formula variable.

Take for example the case that we want to perform a transient analysis. For every time step the displacement should be increased by 6 mm:

enter this to the Formula field:
Variable "time"; Real MATC "0.006*tx"

This code has the following syntax:

  • the prefix Variable specifies that the displacement is not a constant but a variable
  • the variable is the current time
  • the displacement values are returned as Real (floating point value)
  • MATC is the prefix for the Elmer solver that the following code is a formula
  • tx is always the name of the variable in MATC formulas, no matter that tx is in our case actually t

Notes